jawbertsc
well antenna gain is a misnomer somewhat it depends on length of the antenna cable and its resistance as well and such. I'd check to see that your cable is not crimped or the conncetions are not lose or damaged that will kill signal as much as anything else. Gain don't mean anything if its goin nowhere do to a faulty connection.

W G
Here's a good excerpt for you for antenna decibel ratings: The gain of an antenna is a passive phenomenon - power is not added by the antenna, but simply redistributed to provide more radiated power in a certain direction than would be transmitted by an isotropic antenna. If an antenna has a positive gain in some directions, it must have a negative gain in other directions as energy is conserved by the antenna. The gain that can be achieved by an Antenna is therefore trade-off between the range of directions that must be covered by an Antenna and the gain of the antenna. For example, a dish antenna on a spacecraft has a very large gain, but only over a very small range of directions - it must be accurately pointed at earth - but a radio transmitter has a very small gain as it is required to radiate in all directions. ... The ultimate figure of merit for all receiving antennas is the G/T (pronounced "G over T"); that is, the gain of the antenna (in dB) minus the noise temperature of the receiving system (in dB). A typical C-band system will have a G/T of around 20 dB/K, while most Ku-band digital direct to home systems have a G/T of 12.7 dB/K. The more powerful the satellite signal, the lower the G/T value that will be needed at the receiving system down on the ground. WG